In agriculture there are numerous applications in which implements must be moved over a field by means of a self-propelled vehicle with the intention that the implements follow a desired reference path in order, for example, to harvest produce from a field, to cultivate the soil or to spread materials such as seed or fertilizer on a field. In the past the vehicle was steered by a driver for this purpose and the implement, attached rigidly to a three-point linkage or to a coupling of the towing vehicle by means of a draw-bar, followed the manually or automatically steered vehicle. However, it is not always possible to adhere precisely to the reference path of the implement because of the different movement paths of the vehicle and of the implement.
Furthermore, there have been proposed automatic arrangements (e.g., U.S. Pat. No. 6,865,465 B2 and U.S. Pat. Pub. No. 2011/0112721 A1) in which the vehicle is equipped with a satellite-based position determining system and is guided automatically on a reference path on the basis of the signals of the position determining system, while the implement is displaceable by an actuator in a lateral direction with respect to the vehicle and is likewise provided with a satellite-based position determining system. The actuator is activated on the basis of the signals of the position determining system in such a way that the implement is likewise moved on the reference path. U.S. Pat. No. 7,162,348 B2 describes a similar arrangement in which the vehicle is steered by its position determining system and the position of the implement with respect to the vehicle is finely adjusted by a position determining system of the implement and an associated, actuator.